The Light Blues boss was left dumbstruck as Ian Cathro’s relentless Jambos ran amok at Tynecastle in a devastating 4-1 win.

Gers could have been facing up to a repeat of September’s five-goal Old Firm humiliation had it not been for keeper Wes Foderingham’s late heroics.

And Warburton admitted his team only had themselves to blame.

The Englishman said: “We’ve just lost 4-1. We’re Rangers Football Club, we don’t lose 4-1. We did tonight and I feel frustrated, absolutely.

“We weren’t good enough second half. On Saturday against Motherwell, I thought it was as good as we’ve played in 18 months.

“Tonight, second half was as bad as we’ve played in 18 months if not the worst.”

Gers allowed Krystian Nowak to head the hosts ahead after just four minutes and while Emerson Hyndman - the only outfielder in blue to get pass marks - volleyed them level after 36 minutes, the Glasgow side fell apart after the break.

Jamie Walker smashed home Hearts’ second after Andy Halliday’s slip four minutes into the second period before grabbing another after Don Cowie had tapped home the third.

Warburton - whose side also lost on their last visit to Gorgie back in November - added: “To give away four minutes into the second half is just ludicrous. We win together and we lose together but that was way below the levels of Rangers Football Club.

“I didn’t see it coming. Nobody did, the players or staff. We all have bad days at the office, like last time we were here, but we thought we had learned from the first visit not to give the crowd anything.

“But we gave away schoolboys errors at the start of each half. We have to be better than that.